4.2. Hemodynamic Studies and Evaluation of Right Ventricular Hypertrophy

Rats were anesthetized using an isoflurane precision vaporizer (Smiths Medical, Minneapolis, MN, USA) with anesthetic induction at 5% isoflurane concentration and maintenance at 2.5%. Anesthetized rats were placed in a supine position, spontaneously breathing isoflurane/air mixture through a rodent nosecone. A 22-gauge 1-inch needle connected to a fluid-filled disposable Transpac^® IV transducer (Hospira, Lake Forest, IL, USA) was introduced under the xiphoid process of the animal, and the needle was advanced into the right ventricle. An RV pressure waveform was verified and recorded using an MP100 data acquisition system (BioPac Sytems, Inc., Goleta, CA, USA) and an Apple iMac computer running AcqKnowledge version 3.9.1 (BioPac Sytems, Inc., Goleta, CA, USA). Analyses were carried out on the acquired pressure waveforms using the AcqKnowledge software [86]. For the measurement of right ventricular (RV) hypertrophy, heart ventricles and septum were dissected, dried for 7 days, and weighed. Lungs were collected for histology, protein, and cytokine analyses.